A faulty Fuel Pump directly affects the precise fuel metering of the engine, typically manifested as a deviation of the system oil pressure from the rated value. The Society of Automotive Engineers (SAE) research shows that when the oil pressure is more than 0.5 bar lower than the manufacturer’s set standard (for example, the original requirement is 3.0 bar but it is actually only 2.5 bar), the air flow sensor and the fuel injector’s collaborative calculation is inaccurate, resulting in an air-fuel ratio error of up to ±8%. This state causes the electronic control unit (ECU) to misjudge the increase in fuel injection pulse width compensation, and the additional fuel injection volume may exceed 10%, which is equivalent to wasting 1.5 to 2.0 liters of gasoline per 100 kilometers. EPA test data in 2019 demonstrated that faulty pumps with oil pressure fluctuations exceeding ±0.3 bar exacerbated the fuel consumption rate of the Ford F-150 model by 12.7%.
A worn oil pump motor directly increases the energy consumption of the entire vehicle. Current load tests reveal that power loss caused by brush aging can reduce the operating efficiency from the benchmark value of 85% to 67%. This means that the drive pump body needs to consume an additional 40 watts or more of electricity (about 60 watts under normal load), and the vehicle’s electrical system compensatorily increases the power generation, which is equivalent to consuming an extra 0.8 liters of fuel for every 1,000 kilometers driven. The Cummins engineering team’s statistics on 300,000-kilometer trucks revealed that faulty pumps with an 18% decline in output power reduced the thermal efficiency of diesel engines by 3 percentage points and increased the average annual operating cost by more than 500 US dollars.
The clogging of the fuel filter screen significantly reduces the flow rate and combustion efficiency. The data from the experimental bench confirmed that when the clogging rate of the 34μm pore size filter screen reached 40%, the pump body’s flow rate dropped sharply by 22%. To maintain a benchmark oil pressure of 2.8 bar, the motor speed was forced to increase by 25%, causing a sharp increase in power consumption and raising the circuit impedance to 1.7 times the normal value. At this point, the amplitude of pressure pulsation at the end of the fuel injector exceeds ±0.5 bar, the average diameter of atomized particles increases from 80 microns to 140 microns, the amount of soot generated in the combustion chamber rises by 35%, and the thermal efficiency loss can reach 9%. The Chevrolet Silverado owner survey report indicates that the median increase in fuel consumption for vehicles that fail to replace the filter element in time is 15%.
The failure of closed-loop control caused by sensor offset aggravates the waste of oil. The Angle deviation of the oil level float in the integrated Fuel Pump module exceeding ±5° will cause an error of ±4 liters in the calculated volume of the fuel tank. A typical case is that the 2017 Toyota RAV4’s ECU misjudged the remaining mileage due to sensor jamming, leading to frequent refueling. The actual measured frequency of ineffective refueling increased by 30%. The failure of the seal of the pressure regulating valve caused the flow rate of the pressure relief valve to abnormally increase to 2.1L/min (standard value ≤0.8L/min), forcing the pump body to continuously output at maximum power. The rate of fuel consumption deterioration increased by approximately 1.8% each month. J.D. Power statistics show that such faults account for 37% of fuel system repair reports, with an average annual additional fuel consumption cost of $220.
Precise monitoring of the health index of oil pumps has significant economic benefits. The data from the diagnostic instrument shows that when the standard deviation (SD) of the pump body current waveform exceeds the reference value by 0.15A, or the amplitude of the working noise exceeds 75 decibels, it indicates that the lifespan of the components has decreased by more than 70%. Implementing a preventive replacement strategy can shorten the downtime due to faults by 65%. Fleet operation data confirm that this method reduces the average annual fuel budget per vehicle by more than 300 US dollars. During periods of supply chain fluctuations, this measure has further avoided the cost increase caused by the urgent purchase of premium parts, and the return on investment (ROI) for maintenance has reached 140%.